In 2009-2010, AMD launched the entire 4 chip Evergreen series in 6 months. By previous standards this was a quick pace for a new design, especially since AMD had not previously attempted a 4 chip launch in such a manner. Now in 2012 AMD’s Southern Islands team is hard at work at wrapping up their own launch with new aspirations on quickness. Evergreen may have launched 4 chips in 6 months, but this month AMD will be completing the 3 chip Southern Islands launch in half the time – 3 chips in a mere 3 months.

To that end today AMD is taking the wraps off the final piece of the Southern Islands puzzle: Pitcairn. The middle child of the family, it will be the basis of AMD’s $250+ enthusiast segment Radeon HD 7800 series. We’ve seen AMD capture the high-end with the 7900 series and struggle to control the mainstream market with the 7700 series, but how does the 7800 series fare amidst AMD’s lead in deploying 28nm GPUs? Let’s find out.

AMD GPU Specification Comparison

AMD Radeon HD 7870

AMD Radeon HD 7850

AMD Radeon HD 6970

AMD Radeon HD 6950

AMD Radeon HD 5870

Stream Processors

1280

1024

1536

1408

1600

Texture Units

80

64

96

88

80

ROPs

32

32

32

32

32

Core Clock

1000MHz

860MHz

880MHz

800MHz

850MHz

Memory Clock

4.8GHz GDDR5

4.8GHz GDDR5

5.5GHz GDDR5

5.0GHz GDDR5

4.8GHz GDDR5

Memory Bus Width

256-bit

256-bit

256-bit

256-bit

256-bit

Frame Buffer

2GB

2GB

2GB

2GB

1GB

FP64

1/16

1/16

1/4

1/4

1/5

Transistor Count

2.8B

2.8B

2.64B

2.64B

2.15B

PowerTune Limit

190W

150W

250W

200W

N/A

Manufacturing Process

TSMC 28nm

TSMC 28nm

TSMC 40nm

TSMC 40nm

TSMC 40nm

Architecture

GCN

GCN

VLIW4

VLIW4

VLIW5

Price Point

$350

$250

N/A

N/A

N/A

So what exactly is Pitcairn? In a nutshell, take Cape Verde (7700) and double it, and you have Pitcairn. Pitcairn has twice the number of CUs, twice the number of ROPs, twice the memory bandwidth, and of particular importance twice as many geometry engines on the frontend. This works out to 1280 SPs among 20 CUs – organized as a doubling Cape Verde’s interesting 4/3/3 configuration – 80 texture units, 32 ROPs, 512KB L2 cache, and a 256-bit memory bus. Compared to Tahiti, Pitcairn still has 12 fewer CUs and as a result less shader and texturing performance along with the narrower memory bus, but it has the same number of ROPs and the same frontend as its bigger brother, which as we’ll see creates some very interesting situations.

On the functionality side of things, the Cape Verde comparisons continue. As with all Southern Islands family parts, Pitcairn supports things such as DX10+ SSAA, PowerTune, Fast HDMI support, partially resident textures, D3D 11.1 support, and the still-AWOL Video Codec Engine (VCE). FP64 support is once again present, and like Cape Verde it’s a performance-limited implementation for compatibility and software development purposes, with FP64 performance limited to 1/16th FP32 performance.

AMD’s Pitcairn cards will be the Radeon HD 7870 GHz Edition and the Radeon HD 7850. The 7870 is a full Pitcairn, clocked at 1000MHz core and paired with 2GB of GDDR5 running at 4.8GHz. It has a PowerTune limit of 190W while AMD puts its typical board power draw closer to 175, meanwhile idle power consumption is around 10W with a long idle of 3W like the rest of Southern Islands. As for the 7850 it’s the typical lower tier part, featuring 16 active CUs (1024 SPs), an 860MHz core clock, and the same 2GB of GDDR5 running at 4.8GHz as its counterpart, giving it roughly 68% the shading/texturing performance and 86% of the ROP & frontend performance of the 7870. The PowerTune limit is 150W with a typical board power of 130W, and the same 10W/3W idle power consumption as the 7870.

Altogether the 7800 series isn’t just the successor to the Barts based 6800 series in name but also the successor to the 6800 in design. This includes not only power consumption, with one card being a sub-150W part, but also with regards to things such as CrossFire, where it features a single CF connector. Interestingly enough even though Barts was already a fairly small chip for its performance, Pitcairn takes this one step further with a die size of 212mm2, which in turn contains 2.8B transistors, only 160M more than Cayman. As we’ll see when we get to our benchmarks, this makes Pitcairn a surprisingly small chip given its 6970+ performance.

Speaking of the 6970, let’s talk about the 7800 series’ competition. As AMD began winding down Cayman (6900 series) almost immediately with the launch of the 7900 series, at this point the 6900 market has effectively dried up. Having taken themselves out of competition with themselves, AMD’s only competition is NVIDIA’s lineup. From a performance and price basis the 7870 and 7850 don’t map particularly well to any specific NVIDIA products, but generally speaking they’re targeted against the GTX 570 and GTX 560 Ti respectively.

With AMD targeting the ~$320 570 and ~$210 560 Ti and given their conservative pricing on the rest of Southern Islands, it should come as no surprise that the 7800 series is priced equally conservatively. The 7870 will have an MSRP of $350, while the 7850 will have an MSRP of $250. With the 7800 series completing the launch of Southern Islands, this gives AMD a consistent price structure for the entire family: $550, $450, $350, $250, $159, and $109.

Finally, as far as availability goes this will be a delayed launch. AMD is formally unveiling the 7800 series today, but it will not go on sale until the 19th, 2 weeks from now. AMD has said that this is due to both CeBIT and the Game Developers Conference; AMD and their partners want to be able to show off the 7800 series to their respective attendees at those events, with both events being far too large to keep the 7800 under wraps. This delayed launch also means that partner cards aren’t quite ready yet, so we only have AMD’s reference cards on hand. We’ll be taking a look at partner cards later this month.

6870's currently retail for $189.99 - $209.99 original price was $249.99

I just checked these numbers from 3 retailer

7770 is a weaker card then the 6870, sure but performance per dollar is actually a little better with the 7770. Considering the lack of competition from Nvidia why would AMD reduce the price to performance ratio that exists. AMD is selling you more features for a better value card.

When Kepler arrives AMD price's could go down if Nvidia prices it that way. If Kepler is all the #$%^ it's hyped to be AMD will counter it with a price drop then we all win. Looking at ATI/AMD's history something they have always offered the customer, superior price/performance of the competition.

AMD will always be better price to performance for less while Nvidia justifies there inflated prices with CUDA, PhysX, TWIMTBP and of course better driver support.

The value of performance will remain as is. Like a commodity on the stock exchange, why would Nvidia devalue there own stock or at least so quickly?Reply

There is something REALLY odd about 560 TI numbers on ELDERS SCROLL V.

Under 7770 REVIEW it shows 7770 right above 550 TI and on the top of all them is a standard GTX 560 with like 46 fps and here, on this review it shows the GTX 560 TI with like 36 fps. The settings look just like the same..

Please correct that because it is looking like the GTX 560 TI is worse than the 7770, wich it isnt by at least a mile.Reply

With a 7770 the power consumption is below that of the Radeon HD 6870 and GeForce GTX 560 Ti, while still delivering the same gameplay experience of those video cards. About 2%-7% slower then 560 Ti.Reply